Effect of cyclophosphamide combined with glucocorticoid therapy on idiopathic membranous nephropathy: A multicenter open-label randomized controlled trial

OBJECTIVE

We aimed to evaluate the effect of cyclophosphamide combined with glucocorticoid therapy on idiopathic membranous nephropathy through a multicenter open-label randomized controlled trial.

MATERIALS AND METHODS

92 patients with idiopathic membranous nephropathy admitted from March 2020 to September 2022 were included and assigned to a control group (n = 46) and a research group (n = 46) using a random number table. The control group was given glucocorticoid, and the research group was given cyclophosphamide combined with glucocorticoid. Clinical efficacy, renal function-related indicators (serum creatinine, blood urea nitrogen and albumin, and 24-hour urine protein quantification), inflammatory factors (interleukin (IL)-6, IL-18, transforming growth factor-β, and tumor necrosis factor-α), immune function-related indicators (anti-phospholipase A2 receptor antibody, and T-lymphocyte subsets), oxidative stress-related indicators (heme oxygenase-1, superoxide dismutase, malondialdehyde, and nitric oxide), blood lipid-related indicators (total cholesterol, triacylglycerol, and low-density lipoprotein), and adverse reactions were compared.

RESULTS

The overall remission rate of the research group was higher than that of the control group (93.48 vs. 78.26%, p < 0.05). After treatment, the research group had lower levels of 24-hour urine protein quantification, serum creatinine, blood urea nitrogen, IL-6, IL-18, transforming growth factor-β, tumor necrosis factor-α, heme oxygenase-1, malondialdehyde, anti-phospholipase A2 receptor antibody, CD8+, total cholesterol, triacylglycerol and low-density lipoprotein, higher levels of albumin, superoxide dismutase, nitric oxide, and CD4+ and a higher CD4+/CD8+ ratio than the control group (p < 0.05).

CONCLUSION

Cyclophosphamide combined with glucocorticoid therapy is effective for improving the overall remission rate and can suppress inflammatory responses and oxidative stress in patients with idiopathic membranous nephropathy.

Epileptic Seizure Prediction Using Attention Augmented Convolutional Network

Early seizure prediction is crucial for epilepsy patients to reduce accidental injuries and improve their quality of life. Identifying pre-ictal EEG from the inter-ictal state is particularly challenging due to their nonictal nature and remarkable similarities. In this study, a novel epileptic seizure prediction method is proposed based on multi-head attention (MHA) augmented convolutional neural network (CNN) to address the issue of CNN's limit of capturing global information of input signals. First, data enhancement is performed on original EEG recordings to balance the pre-ictal and inter-ictal EEG data, and the EEG recordings are sliced into 6-second-long EEG segments. Subsequently, EEG time-frequency distribution is obtained using Stockwell transform (ST), and the attention augmented convolutional network is employed for feature extraction and classification. Finally, post-processing is utilized to reduce the false prediction rate (FPR). The CHB-MIT EEG database was used to evaluate the system. The validation results showed a segment-based sensitivity of 98.24% and an event-based sensitivity of 94.78% with a FPR of 0.05/h were yielded, respectively. The satisfying results of the proposed method demonstrate its possible potential for clinical applications.

Relationship between Social Support, Sarcopenia, and Cognitive Impairment in Chinese Community-Dwelling Older Adults

BACKGROUND

Cognitive impairment and sarcopenia have become important challenges for the growing aging population. Social support has been shown to protect against cognitive impairment, but its impact on sarcopenia remains unknown. The purpose of this study was to explore the correlation between social support, sarcopenia, and cognitive impairment in Chinese older adults.

METHOD

A multi-stage whole group sampling method was used to conduct a cross-sectional survey of 720 community-dwelling older people in Shanghai. The definition of sarcopenia was in accordance with the criteria of the Asian Working Group for Sarcopenia (AWGS) 2019. Cognitive impairment was evaluated using a computerized neuropsychological assessment device that had been previously validated. Social support was assessed using the Social Support Rate Scale. Logistic regression analyses were conducted to explore the relationship between social support cognitive impairment and sarcopenia, fully adjusting for all potential confounding factors.

RESULTS

Our study found that 230 (31.94%) of the participants had cognitive impairment and 97 (13.47%) of the participants had sarcopenia. The mean social support score was 35.10 ± 7.54. Besides, the results showed that cognitive impairment was associated with sarcopenia (OR:1.650, 95% CI: 1.048, 2.596, P=0.030) after adjusting for confounding factors. Older adults with high level social support had the lowest risk of cognitive impairment (OR: 0.297, 95% CI: 0.115, 0.680, P=0.021) and sarcopenia (OR: 0.113, 95% CI: 0.031, 0.407, P=0.001), respectively.

CONCLUSION

Our analysis revealed that high level social support was negatively associated with sarcopenia and cognitive impairment. These findings provide strong support for the health promotion effect of social networks against sarcopenia and cognitive impairment in Chinese community-dwelling older adults, with important implications for healthcare policy makers.

Design of single-phased magnesium alloys with typically high solubility rare earth elements for biomedical applications: Concept and proof

Rare earth elements (REEs) have been long applied in magnesium alloys, among which the mischmetal-containing WE43 alloy has already got the CE mark approval for clinical application. A considerable amount of REEs (7 wt%) is needed in that multi-phased alloy to achieve a good combination of mechanical strength and corrosion resistance. However, the high complex RE addition accompanied with multiple second phases may bring the concern of biological hazards. Single-phased Mg-RE alloys with simpler compositions were proposed to improve the overall performance, i.e., “Simpler alloy, better performance”. The single-phased microstructure can be successfully obtained with typical high-solubility REEs (Ho, Er or Lu) through traditional smelting, casting and extrusion in a wide compositional range. A good corrosion resistance with a macroscopically uniform corrosion mode was guaranteed by the homogeneously single-phased microstructure. The bimodal-grained structure with plenty of sub-grain microstructures allow us to minimize the RE addition to <1 wt%, without losing mechanical properties. The single-phased Mg-RE alloys show comparable mechanical properties to the clinically-proven Mg-based implants. They exhibited similar in-vitro and in-vivo performances (without local or systematic toxicity in SD-rats) compared to a high purity magnesium. In addition, metal elements in our single-phased alloys can be gradually excreted through the urinary system and digestive system, showing no consistent accumulation of RE in main organs, i.e., less burden on organs. The novel concept in this study focuses on the simplification of Mg-RE based alloys for biomedical purpose, and other biodegradable metals with single-phased microstructures are expected to be explored.

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A concept of developing single-phased biodegradable magnesium alloys was proposed.

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Single-phased magnesium alloys with bimodal-grained structures were obtained.

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Good strength and corrosion resistance synergy was achieved in the alloys.

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Significantly reduced rare earth addition is beneficial to the biocompatibility.

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Simpler alloy helps to lower the possible biological risks of Mg related implants.

Recent advances on the mechanical behavior of zinc based biodegradable metals focusing on the strain softening phenomenon

Zinc based biodegradable metals (BMs) show great potential to be used in various biomedical applications, owing to their superior biodegradability and biocompatibility. Some high-strength (ultimate tensile strength > 600 MPa) Zn based BMs have already been developed through alloying and plastic working, making their use in load-bearing environments becomes a reality. However, different from Mg and Fe based BMs, Zn based BMs exhibit significant "strain-softening" effect that leads to limited uniform deformation. Non-uniform deformation is detrimental to Zn based devices or implants, which will possibly lead to unexpected failure. People might be misled by the considerable fracture elongation of Zn based BMs. Thus, it is important to specify uniform elongation as a term of mechanical requirements for Zn based BMs. In this review, recent advances on the mechanical properties of Zn based BMs have been comprehensively summarized, especially focusing on the strain softening phenomenon. At first, the origin and evaluation criteria of strain softening were introduced. Secondly, the effects of alloying elements (including element type, single or multiple addition, and alloying content) and microstructural characteristics (grain size, constituent phase, phase distribution, etc.) on mechanical properties (especially for uniform elongation) of Zn based BMs were summarized. Finally, how to get a good balance between strength and uniform elongation was generally discussed based on the service environment. In addition, possible ways to minimize or eliminate the strain softening effect were also proposed, such as controlling of twins, solute clusters, and grain boundary characteristics. All these items above would be helpful to understand the mechanical instability of Zn based BMs, and to make the full usage of them in the future medical device design. STATEMENT OF SIGNIFICANCE: Biodegradable metals (BMs) is a hotspot in the field of metallic biomaterials. Fracture elongation is normally adopted to quantify the deformability of Mg and Fe based BMs owing to their negligible necking strain, yet the strain softening would occur in Zn based BMs, which is extremely detrimental to performance of their medical device. In this review paper, a better understanding the mechanical performance of Zn-based BMs with the term "uniform elongation" instead of "fracture elongation" was depicted, and possible ways to minimize or eliminate the strain softening effect were also proposed, such as twins, solute clusters, self-stable dislocation network, and grain boundary characteristics. It would be helpful to understand the mechanical instability of Zn based BMs and making full usage of it in the future medical device design.

Fluorescent In Situ 3D Visualization of Dynamic Corrosion Processes of Magnesium Alloys

Magnesium (Mg) alloys as implant materials with excellent biodegradation ability have promising clinical applications for tissue repair and restoration. Although the corrosion processes of Mg alloys in biophysiological media are closely related with their biodegradation ability, only limited methods have been developed for characterization of their corrosion processes, including electrochemical analysis, weight loss measurement, and hydrogen evolution analysis. Moreover, these methods suffer from drawbacks of poor spatiotemporal resolution, static observation, and tedious operation. To tackle these challenges, we herein developed a fluorescent probe PSPA for in situ 3D monitoring of the dynamic corrosion processes of Mg alloys on the basis of its selective turn-on detection ability toward magnesium hydroxide [Mg(OH)₂], which is the main corrosion product of Mg alloys in biophysiological media. As far as we know, this is the first example of a fluorescent probe for the monitoring of corrosion processes of Mg alloys in biophysiological media. We believe this fluorescence analysis method with easy operation and high spatiotemporal resolution advantages will contribute greatly to the clinical applications of Mg alloy implants.

Biomimicking Bone-Implant Interface Facilitates the Bioadaption of a New Degradable Magnesium Alloy to the Bone Tissue Microenvironment

The most critical factor determining the success of biodegradable bone implants is the host tissue response, which greatly depends on their degradation behaviors. Here, a new magnesium-based implant, namely magnesium-silicon-calcium (Mg-0.2Si-1.0Ca) alloy, that coordinates its biodegradation along with the bone regenerative process via a self-assembled, multilayered bone-implant interface is designed. At first, its rapid biocorrosion contributes to a burst release of Mg2+ , leading to a pro-osteogenic immune microenvironment in bone. Meanwhile, with the simultaneous intervention of Ca and Si in the secondary phases of the new alloy, a hierarchical layered calcified matrix is rapidly formed at the degrading interface that favored the subsequent bone mineralization. In contrast, pure Mg or Mg-0.2Si alloy without the development of this interface at the beginning will unavoidably induce detrimental bone loss. Hence, it is believed this biomimicking interface justifies its bioadaptability in which it can modulate its degradation in vivo and accelerate bone mineralization.

PDLLA-Zn-nitrided Fe bioresorbable scaffold with 53-μm-thick metallic struts and tunable multistage biodegradation function

Balancing the biodegradability and mechanical integrity of a bioresorbable scaffold (BRS) with time after implantation to match the remodeling of the scaffolded blood vessel is important, but a key challenge in doing so remains. This study presents a novel intercalated structure of a metallic BRS by introducing a nanoscale Zn sacrificial layer between the nitrided Fe platform and the sirolimus-carrying poly(d,l-lactide) drug coating. The PDLLA-Zn-FeN BRS shows a multistage biodegradation behavior, maintaining mechanical integrity at the initial stage and exhibiting accelerated biodegradation at the subsequent stage in both rabbit abdominal aortas and human coronary arteries, where complete biodegradation was observed about 2 years after implantation. The presence of the nanoscale Zn sacrificial layer with an adjustable thickness also contributes to the tunable biodegradation of BRS and allows the reduction of the metallic strut thickness to 53 μm, with radial strength as strong as that of the current permanent drug-eluting stents.

Degradation behaviors and in-vivo biocompatibility of a rare earth- and aluminum-free magnesium-based stent

Biodegradable stents can provide scaffolding and anti-restenosis benefits in the short term and then gradually disappear over time to free the vessel, among which the Mg-based biodegradable metal stents have been prosperously developed. In the present study, a Mg-8.5Li (wt.%) alloy (RE- and Al-free) with high ductility (> 40%) was processed into mini-tubes, and further fabricated into finished stent through laser cutting and electropolishing. In-vitro degradation test was performed to evaluate the durability of this stent before and after balloon dilation. The influence of plastic deformation and residual stress (derived from the dilation process) on the degradation was checked with the assistance of finite element analysis. In addition, in-vivo degradation behaviors and biocompatibility of the stent were evaluated by performing implantation in iliac artery of minipigs. The balloon dilation process did not lead to deteriorated degradation, and this stent exhibited a decent degradation rate (0.15 mm/y) in vitro, but divergent result (> 0.6 mm/y) was found in vivo. The stent was almost completely degraded in 3 months, revealing an insufficient scaffolding time. Meanwhile, it did not induce possible thrombus, and it was tolerable by surrounding tissues in pigs. Besides, endothelial coverage in 1 month was achieved even under the severe degradation condition. In the end, the feasibility of this stent for treatment of benign vascular stenosis was generally discussed, and perspectives on future improvement of Mg-Li-based stents were proposed.

Biomimetic Ti-6Al-4V alloy/gelatin methacrylate hybrid scaffold with enhanced osteogenic and angiogenic capabilities for large bone defect restoration

Titanium-based scaffolds are widely used implant materials for bone defect treatment. However, the unmatched biomechanics and poor bioactivities of conventional titanium-based implants usually lead to insufficient bone integration. To tackle these challenges, it is critical to develop novel titanium-based scaffolds that meet the bioadaptive requirements for load-bearing critical bone defects. Herein, inspired by the microstructure and mechanical properties of natural bone tissue, we developed a Ti–6Al–4V alloy (TC4)/gelatin methacrylate (GelMA) hybrid scaffold with dual bionic features (GMPT) for bone defect repair. GMPT is composed of a hard 3D-printed porous TC4 metal scaffold (PT) backbone, which mimics the microstructure and mechanical properties of natural cancellous bone, and a soft GelMA hydrogel matrix infiltrated into the pores of PT that mimics the microenvironment of the extracellular matrix. Ascribed to the unique dual bionic design, the resultant GMPT demonstrates better osteogenic and angiogenic capabilities than PT, as confirmed by the in vitro and rabbit radius bone defect experimental results. Moreover, controlling the concentration of GelMA (10%) in GMPT can further improve the osteogenesis and angiogenesis of GMPT. The fundamental mechanisms were revealed by RNA-Seq analysis, which showed that the concentration of GelMA significantly influenced the expression of osteogenesis- and angiogenesis-related genes via the Pi3K/Akt/mTOR pathway. The results of this work indicate that our dual bionic implant design represents a promising strategy for the restoration of large bone defects.

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A novel TC4/GelMA hybrid scaffold (GMPT) was designed to mimic natural bone microstructure and mechanical property.

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The GMPT with 10 wt% of GelMA showed best capability for promoting osteogenesis and angiogenesis.

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A bioactive soft surface with suitable stiffness can activate focal adhesion pathway and the downstream PI3K/AKT pathway.

Magnetic resonance (MR) safety and compatibility of a novel iron bioresorbable scaffold

Fully bioresorbable scaffolds have been designed to overcome the limitations of traditional drug-eluting stents (DESs), which permanently cage the native vessel wall and pose possible complications. The ultrathin-strut designed sirolimus-eluting iron bioresorbable coronary scaffold system (IBS) shows comparable mechanical properties to traditional DESs and exhibits an adaptive degradation profile during target vessel healing, which makes it a promising candidate in all-comers patient population. For implanted medical devices, magnetic resonance (MR) imaging properties, including MR safety and compatibility, should be evaluated before its clinical use, especially for devices with intrinsic ferromagnetism. In this study, MR safety and compatibility of the IBS scaffold were evaluated based on a series of well-designed in-vitro, ex-vivo and in-vivo experiments, considering possible risks, including scaffold movement, over-heating, image artifact, and possible vessel injury, under typical MR condition. Traditional ASTM standards for MR safety and compatibility evaluation of intravascular devices were referred, but not only limited to that. The unique time-relevant MR properties of bioresorbable scaffolds were also discussed. Possible forces imposed on the scaffold during MR scanning and MR image artifacts gradually decreased along with scaffold degradation/absorption. Rigorous experiments designed based on a scientifically based rationale revealed that the IBS scaffold is MR conditional, though not MR compatible before complete absorption. The methodology used in the present study can give insight into the MR evaluation of magnetic scaffolds (bioresorbable) or stents (permanent).

Comparative in vitro study on binary Mg-RE (Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) alloy systems

Correct selection of alloying elements is important for developing novel biodegradable magnesium alloys with superior mechanical and biological performances. In contrast to various reports on nutrient elements (Ca, Zn, Sr, etc.) as alloying elements of biomedical magnesium alloys, there is limited information about how to choose the right rare earth elements (REEs) as alloying elements of magnesium. In this work, 16 kinds of REEs were individually added into Mg, including Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Du, Ho, Er, Tm, Yb and Lu, to fabricate binary Mg-RE model alloys with different composition points. Under the same working history, comparative studies were undertaken and the impact of each kind of rare earth element on the microstructure, mechanical property, corrosion behavior and biocompatibility of Mg were investigated. The corresponding influence level for the 16 kinds of REEs were ranked. The results showed that the second phases were detected in some Mg-RE alloys, which were mainly composed of Mg₁₂RE. By adding different REEs into Mg with proper contents, the mechanical properties of resulting Mg-RE binary alloys could be adjusted in wide range. The corrosion resistance of Mg-light REE alloys was generally better than Mg-heavy REE alloys. As for biocompatibility, Mg-RE model alloys showed no cytotoxic effect on MC3T3-E1 cells. The hemolysis rates of all experimental Mg-RE model alloys were lower than 5% except for Mg-Lu alloy model. In general, the addition of different REEs into Mg could improve its performance from different aspects. This work provides a better understanding on suitable REEs as alloying elements for magnesium, and the future R&D direction on biomedical Mg-RE alloys was proposed. STATEMENT OF SIGNIFICANCE: In contrast to various reports on nutrient elements (Ca, Zn, Sr, etc.) as alloying elements of biomedical magnesium alloys, until now there is limited information about how to choose the right rare earth elements (REEs) as alloying elements of magnesium. In this work, comparative studies were undertaken by individually adding 16 kinds of REEs, including Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Du, Ho, Er, Tm, Yb and Lu, into Mg to fabricate binary Mg-RE model alloys, with different composition points, then the impact of each kind of rare earth element on the microstructure, mechanical property, corrosion behavior and biocompatibility of Mg under the same working history were investigated, and the corresponding influence level for the 16 kinds of REEs were ranked. This work provides a better understanding on suitable REEs as alloying elements for magnesium, and the future R&D direction on biomedical Mg-RE alloys was proposed.

In vitro and in vivo studies of Mg-30Sc alloys with different phase structure for potential usage within bone

Proper alloying magnesium with element scandium (Sc) could transform its microstructure from α phase with hexagonal closed-packed (hcp) structure into β phase with body-cubic centered (bcc) structure. In the present work, the Mg-30 wt% Sc alloy with single α phase, dual phases (α + β) or β phase microstructure were developed by altering the heat-treatment routines and their suitability for usage within bone was comprehensively investigated. The β phased Mg-30 wt% Sc alloy showed the best mechanical performance with ultimate compressive strength of 603 ± 39 MPa and compressive strain of 31 ± 3%. In vitro degradation test showed that element scandium could effectively incorporate into the surface corrosion product layer, form a double-layered structure, and further protect the alloy matrix. No cytotoxic effect was observed for both single α phased and β phased Mg-30 wt% Sc alloys on MC3T3 cell line. Moreover, the β phased Mg-30 wt%Sc alloy displayed acceptable corrosion resistance in vivo (0.06 mm y^-1) and maintained mechanical integrity up to 24 weeks. The degradation process did not significantly influence the hematology indexes of inflammation, hepatic or renal functions. The bone-implant contact ratio of 75 ± 10% after 24 weeks implied satisfactory integration between β phased Mg-30 wt%Sc alloy and the surrounding bone. These findings indicate a potential usage of the bcc-structured Mg-Sc alloy within bone and might provide a new strategy for future biomedical magnesium alloy design. STATEMENT OF SIGNIFICANCE: Scandium is the only rare earth element that can transform the matrix of magnesium alloy into bcc structure, and Mg-30 wt%Sc alloy had been recently reported to exhibit shape memory effect. The aim of the present work is to study the feasibility of Mg-30 wt%Sc alloy with different constitutional phases (single α phase, single β phase or dual phases (α + β)) as biodegradable orthopedic implant by in vitro and in vivo testings. Our findings showed that β phased Mg-30 wt%Sc alloy which is of bcc structure exhibited improved strength and superior in vivo degradation performance (0.06 mm y^-1). No cytotoxicity and systematic toxicity were shown for β phased Mg-30 wt%Sc alloy on MC3T3 cell model and rat organisms. Moreover, good osseointegration, limited hydrogen gas release and maintained mechanical integrity were observed after 24 weeks' implantation into the rat femur bone.

In Vitro and in Vivo Studies on Biomedical Magnesium Low-Alloying with Elements Gadolinium and Zinc for Orthopedic Implant Applications

Ternary magnesium alloys with low combined addition of elements gadolinium and zinc were developed in the present work, with their microstructures, mechanical properties, in vitro degradation behaviors, and cytotoxicity being systematically studied. Furthermore, the Mg-1.8Zn-0.2Gd alloy, with the best in vitro performance, was implanted into Sprague Dawley rats to examine its in vivo degradation performance for up to 6 months. It was found that Mg-1.8Zn-0.2Gd, composed of a single α-Mg phase, owned excellent strength and toughness that were comparable to the CE marked MAGNEZIX, the mischmetal added Mg alloy. Owing to the uniform single-phased microstructure, the degradation rate of this alloy was around 0.12 mm/y measured by electrochemical testing, which was comparable to high purity magnesium. Moreover, the Mg-1.8Zn-0.2Gd alloy exhibited no cytotoxicity to L929, MG63, and VSMC cells. In vivo degradation characterized by micro-computed tomography revealed that the Mg-1.8Zn-0.2Gd implant could maintain structural integrity in the first 2 months, and serious degradation could be observed after 6 months. A remarkable 100% survival rate of experimental animals was observed with no negative effects on bone tissues. The implant and the surrounding bone were well integrated within 2 months, implying good biocompatibility and osteoconductivity of the experimental alloy. On the basis of the above findings, the feasibility of Mg-Zn-Gd alloys for use as orthopedic implants was systematically discussed. This study provides a new strategy for development of high-performance Mg-rare earth (RE)-based alloys with superior mechanical properties and corrosion resistance while effectively avoiding the possible standing toxic effect of RE elements.

THE DECADE OF THE RABiT (2005-15)

The RABiT (Rapid Automated Biodosimetry Tool) is a dedicated Robotic platform for the automation of cytogenetics-based biodosimetry assays. The RABiT was developed to fulfill the critical requirement for triage following a mass radiological or nuclear event. Starting from well-characterized and accepted assays we developed a custom robotic platform to automate them. We present here a brief historical overview of the RABiT program at Columbia University from its inception in 2005 until the RABiT was dismantled at the end of 2015. The main focus of this paper is to demonstrate how the biological assays drove development of the custom robotic systems and in turn new advances in commercial robotic platforms inspired small modifications in the assays to allow replacing customized robotics with 'off the shelf' systems. Currently, a second-generation, RABiT II, system at Columbia University, consisting of a PerkinElmer cell::explorer, was programmed to perform the RABiT assays and is undergoing testing and optimization studies.

Design of a Virtual Reality System for Affect Analysis in Facial Expressions (VR-SAAFE); Application to Schizophrenia

Schizophrenia is a life-long, debilitating psychotic disorder with poor outcome that affects about 1% of the population. Although pharmacotherapy can alleviate some of the acute psychotic symptoms, residual social impairments present a significant barrier that prevents successful rehabilitation. With limited resources and access to social skills training opportunities, innovative technology has emerged as a potentially powerful tool for intervention. In this paper, we present a novel virtual reality (VR)-based system for understanding facial emotion processing impairments that may lead to poor social outcome in schizophrenia. We henceforth call it a VR System for Affect Analysis in Facial Expressions (VR-SAAFE). This system integrates a VR-based task presentation platform that can minutely control facial expressions of an avatar with or without accompanying verbal interaction, with an eye-tracker to quantitatively measure a participants real-time gaze and a set of physiological sensors to infer his/her affective states to allow in-depth understanding of the emotion recognition mechanism of patients with schizophrenia based on quantitative metrics. A usability study with 12 patients with schizophrenia and 12 healthy controls was conducted to examine processing of the emotional faces. Preliminary results indicated that there were significant differences in the way patients with schizophrenia processed and responded towards the emotional faces presented in the VR environment compared with healthy control participants. The preliminary results underscore the utility of such a VR-based system that enables precise and quantitative assessment of social skill deficits in patients with schizophrenia.

Influence of biocompatible metal ions (Ag, Fe, Y) on the surface chemistry, corrosion behavior and cytocompatibility of Mg-1Ca alloy treated with MEVVA

Mg-1Ca samples were implanted with biocompatible alloy ions Ag, Fe and Y respectively with a dose of 2×10(17)ionscm(-2) by metal vapor vacuum arc technique (MEVVA). The surface morphologies and surface chemistry were investigated by SEM, AES and XPS. Surface changes were observed after all three kinds of elemental ion implantation. The results revealed that the modified layer was composed of two sublayers, including an outer oxidized layer with mixture of oxides and an inner implanted layer, after Ag and Fe ion implantation. Y ion implantation induced an Mg/Ca-deficient outer oxidized layer and the distribution of Y along with depth was more homogeneous. Both electrochemical test and immersion test revealed accelerated corrosion rate of Ag-implanted Mg-1Ca and Fe-implanted Mg-1Ca, whereas Y ion implantation showed a short period of protection since enhanced corrosion resistance was obtained by electrochemical test, but accelerated corrosion rate was found by long period immersion test. Indirect cytotoxicity assay indicated good cytocompatibility of Y-implanted Mg-1Ca. Moreover, the corresponding corrosion mechanisms involving implanting ions into magnesium alloys were proposed, which might provide guidance for further application of plasma ion implantation to biodegradable Mg alloys.

The G12/13-RhoA signaling pathway contributes to efficient lysophosphatidic acid-stimulated cell migration

The membrane redistribution and phosphorylation of focal adhesion kinase (FAK) have been reported to be important for cell migration. We previously showed that Lysophosphatidic acid (LPA) induced FAK membrane redistribution and autophosphorylation in ovarian cancer SK-OV3 cells and the signaling pathway consisting of Gi-Ras-MEKK1 mediated LPA-induced FAK membrane redistribution but not FAK autophosphorylation. We also showed that the disruption of the Gi-Ras-MEKK1 pathway led to a significant reduction in LPA-stimulated cell migration. These findings raised the question of whether LPA-induced FAK autophosphorylation was required for LPA-stimulated cell migration and what signaling mechanism was involved in LPA-induced FAK autophosphorylation. In this study, we expressed the membrane anchored wild-type FAK (CD2-FAK) in SK-OV3 cells and found that the expression of CD2-FAK greatly rescued LPA-stimulated cell migration in Gi or Ras-inhibited cells. However, Gi inhibitor pertussis toxin or dominant-negative H-Ras still significantly inhibited LPA-stimulated cell migration in cells expressing the membrane anchored FAK containing a mutation in the autophosphorylation site [CD2-FAK(Y397A)]. These results suggest that FAK autophosphorylation plays a role in LPA-stimulated cell migration. With the aid of p115RhoGEF-RGS, G12 and G13 minigenes to inhibit G12/13, we found that the G12/13 pathway was required for LPA-induced FAK autophosphorylation and efficient cell migration. Moreover, LPA activated RhoA and Rho kinase (ROCK) in a G12/13-dependent manner and their activities were required for LPA-induced FAK autophosphorylation. However, Rho or ROCK inhibitors displayed no effect on LPA-induced FAK membrane redistribution although they abolished LPA-induced cytoskeleton reorganization. Our studies show that the G12/13-RhoA-ROCK signaling pathway mediates LPA-induced FAK autophosphorylation and contributes to LPA-stimulated cell migration.

Antagonism of delta(2)-opioid receptors by naltrindole-5'-isothiocyanate attenuates heroin self-administration but not antinociception in rats

delta-Opioid receptors have been implicated in reinforcement processes and antagonists are available that produce long-lasting and selective antagonism of delta-opioid receptors in vivo. This experiment assessed the contribution of delta-opioid receptors to the antinociceptive and reinforcing properties of heroin. The effects of the irreversible delta-antagonist naltrindole-5'-isothiocyanate (5'-NTII) were evaluated on heroin self-administration and hot-plate antinociception in rats. 5'-NTII (10 nmol i.c.v.) shifted the dose-response curve for heroin self-administration downward, increasing the A(50) values on the ascending and descending limbs by approximately 0.5 log units and decreasing the maximum by 33%. 5'-NTII (40 nmol i.c.v.) shifted both limbs of the heroin self-administration dose-effect curve 1.2 log units to the right and decreased the maximum by 90%. Heroin self-administration gradually returned to baseline levels over 7 or 17 days after administration of 10 or 40 nmol 5'-NTII, respectively. 5'-NTII (40 nmol i.c.v.) decreased the self-administration of 0.17 mg/infusion cocaine by 40% while having no effect on responding maintained by 0.33 or 0.67 mg/infusion. 5'-NTII attenuated the antinociceptive effects of deltorphin (delta(2)) in a dose-dependent manner while having no effect on antinociception elicited after i.c. v. administration of [D-Pen(2),D-Pen(5)]-enkephalin (delta(1)) or [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (mu). In addition, the antinociceptive effects of heroin were not significantly affected by 5'-NTII (40 nmol i.c.v.). Therefore, 5'-NTII can attenuate the reinforcing effects of heroin at doses that do not affect its antinociceptive effects. Long-acting delta(2)-opioid antagonists may be beneficial in the treatment of heroin dependence or as adjuncts to reduce the abuse liability of opioid analgesics.

Extraterritorial neuropathic pain correlates with multisegmental elevation of spinal dynorphin in nerve-injured rats

Neuropathic pain is often associated with the appearance of pain in regions not related to the injured nerve. One mechanism that may underlie neuropathic pain is abnormal, spontaneous afferent drive which may contribute to NMDA-mediated central sensitization by the actions of glutamate and by the non-opioid actions of spinal dynorphin. In the present study, injuries to lumbar or sacral spinal nerves elicited elevation in spinal dynorphin content which correlated temporally and spatially with signs of neuropathic pain. The increase in spinal dynorphin content was coincident with the onset of tactile allodynia and thermal hyperalgesia. Injury to the lumbar (L(5)/L(6)) spinal nerves produced elevated spinal dynorphin content in the ipsilateral dorsal spinal quadrant at the L(5) and L(6) spinal segments and in the segments immediately adjacent. Lumbar nerve injury elicited ipsilateral tactile allodynia and thermal hyperalgesia of the hindpaw. In contrast, S(2) spinal nerve ligation elicited elevated dynorphin content in sacral spinal segments and bilaterally in the caudal lumbar spinal cord. The behavioral consequences of S(2) spinal nerve ligation were also bilateral, with tactile allodynia and thermal hyperalgesia seen in both hindpaws. Application of lidocaine to the site of S(2) ligation blocked thermal hyperalgesia and tactile allodynia of the hindpaws suggesting that afferent drive was critical to maintenance of the pain state. Spinal injection of antiserum to dynorphin A((1-17)) and of MK-801 both blocked thermal hyperalgesia, but not tactile allodynia, of the hindpaw after S(2) ligation. These data suggest that the elevated spinal dynorphin content consequent to peripheral nerve injury may drive sensitization of the spinal cord, in part through dynorphin acting directly or indirectly on the NMDA receptor complex. Furthermore, extrasegmental increases in spinal dynorphin content may partly underlie the development of extraterritorial neuropathic pain.

Selective opioid delta agonists elicit antinociceptive supraspinal/spinal synergy in the rat

A multiplicative antinociceptive interaction of morphine activity at supraspinal and spinal sites has been clearly established and is thought to be responsible, in part, for the clinical utility of this compound in normal dose-ranges. While synergistic actions of mu-opioid receptor agonists have been shown, it is unclear whether a similar interaction exists for opioid agonists acting via delta-opioid receptors. Responses to acute nociception were determined with the 52 degrees C hot plate, 52 degrees C warm-water tail-flick and the Hargreaves paw-withdrawal tests. The peptidic opioid delta(1) agonist [D-Pen(2),D-Pen(5)]enkephalin (DPDPE) or delta(2) agonist [D-Ala(2),Glu(4)]deltorphin (DELT) were given into the rostral-ventral medulla (RVM), intrathecally (i.th.) or simultaneously into both the RVM and i.th. (1:1 fixed ratio). Both of the opioid delta agonists produced dose-dependent antinociception in all tests. With the exception of DPDPE in the hot plate test, isobolographic analysis revealed that the supraspinal/spinal antinociceptive interaction for both DPDPE and DELT were synergistic in all nociceptive tests. These data suggest that opioid delta agonists exert a multiplicative antinociceptive interaction between supraspinal and spinal sites to acute noxious stimuli and suggest possibility that compounds acting through delta-opioid receptors may have sufficient potency for eventual clinical application.

A comparison of the potential role of the tetrodotoxin-insensitive sodium channels, PN3/SNS and NaN/SNS2, in rat models of chronic pain

Alterations in sodium channel expression and function have been suggested as a key molecular event underlying the abnormal processing of pain after peripheral nerve or tissue injury. Although the relative contribution of individual sodium channel subtypes to this process is unclear, the biophysical properties of the tetrodotoxin-resistant current, mediated, at least in part, by the sodium channel PN3 (SNS), suggests that it may play a specialized, pathophysiological role in the sustained, repetitive firing of the peripheral neuron after injury. Moreover, this hypothesis is supported by evidence demonstrating that selective "knock-down" of PN3 protein in the dorsal root ganglion with specific antisense oligodeoxynucleotides prevents hyperalgesia and allodynia caused by either chronic nerve or tissue injury. In contrast, knock-down of NaN/SNS2 protein, a sodium channel that may be a second possible candidate for the tetrodotoxin-resistant current, appears to have no effect on nerve injury-induced behavioral responses. These data suggest that relief from chronic inflammatory or neuropathic pain might be achieved by selective blockade or inhibition of PN3 expression. In light of the restricted distribution of PN3 to sensory neurons, such an approach might offer effective pain relief without a significant side-effect liability.

Loss of antiallodynic and antinociceptive spinal/supraspinal morphine synergy in nerve-injured rats: restoration by MK-801 or dynorphin antiserum

The co-administration of morphine at spinal (i.th.) and supraspinal (i.c.v.) sites to the same rat produces antinociceptive synergy, a phenomenon which may underlie the clinical analgesic utility of this drug. In animals with peripheral nerve injury, however, the antinociceptive potency and efficacy of i.th. morphine is significantly decreased. Here, the possible loss of spinal/supraspinal morphine antinociceptive synergy and relationship to elevation of spinal dynorphin content was studied. Ligation of lumbar spinal nerves resulted in elevated dynorphin in the ipsilateral lumbar and sacral spinal cord. In sham-operated rats supraspinal/spinal co-administration of morphine produced synergistic antinociception which was unaffected by i.th. MK-801 or dynorphin A((1-17)) antiserum. In nerve-injured rats, i.th. morphine was inactive against tactile allodynia and showed diminished in potency against acute nociception without supraspinal/spinal antinociceptive synergy. Antiserum to dynorphin A((1-17)) or the non-competitive NMDA antagonist MK-801 increased the antinociceptive potency of i.th. morphine, restored supraspinal/spinal morphine antinociceptive synergy and elicited a dose-related i.th. morphine antiallodynic action. These agents did not demonstrate antinociceptive or antiallodynic activity alone and did not alter morphine actions in sham-operated animals. The loss of spinal/supraspinal antinociceptive synergy and lack of antiallodynic activity of spinal morphine appear to be due to the elevation across multiple spinal segments of dynorphin following nerve injury. Pathological actions of elevated dynorphin may directly or indirectly modulate the NMDA receptor, result in a loss of supraspinal/spinal morphine synergy and may thus account for the decreased clinical analgesic efficacy of morphine in peripheral neuropathies.

Characterization of antiallodynic actions of ALE-0540, a novel nerve growth factor receptor antagonist, in the rat

There is growing evidence that nerve growth factor (NGF) may function as a mediator of persistent pain states. We have identified a novel nonpeptidic molecule, ALE-0540, that inhibits the binding of NGF to tyrosine kinase (Trk) A or both p75 and TrkA (IC50 5.88 +/- 1. 87 microM, 3.72 +/- 1.3 microM, respectively), as well as signal transduction and biological responses mediated by TrkA receptors. ALE-0540 was tested in models of neuropathic pain and thermally-induced inflammatory pain, using two routes of administration, a systemic i.p. and a spinal intrathecal (i.th.) route. Morphine was also tested for comparison in the antiallodynia model using mechanical stimuli. We show that either i.p. or i.th. administration of ALE-0540 in rats produced antiallodynia in the L5/L6 ligation model of neuropathic pain. The calculated A50 values (and 95% confidence intervals) for ALE-0540 administered i.p. and i. th. were 38 (17.5-83) mg/kg and 34.6 (17.3-69.4) microgram, respectively. ALE-0540 given i.th., at doses of 30 and 60 microgram, also blocked tactile allodynia in the thermal sensitization model. Although morphine displayed greater potency [A50 value of 7.1 (5.6-8. 8) mg/kg] than ALE-0540 in anti-allodynic effect when given i.p. to L5/L6-ligated rats, it was not active when administered i.th. These data suggest that a blockade of NGF bioactivity using a NGF receptor antagonist is capable of blocking neuropathic and inflammatory pain and further support the hypothesis that NGF is involved in signaling pathways associated with these pain states. ALE-0540 represents a nonpeptidic small molecule which can be used to examine mechanisms leading to the development of agents for the treatment of pain.

Lack of involvement of capsaicin-sensitive primary afferents in nerve-ligation injury induced tactile allodynia in rats

Tactile allodynia and thermal hyperalgesia, two robust signs of neuropathic pain associated with experimental nerve injury, have been hypothesized to be mechanistically distinguished based on (a) fiber types which may be involved in the afferent input, (b) participation of spinal and supraspinal circuitry in these responses, and (c) sensitivity of these endpoints to pharmacological agents. Here, the possibility that nerve-injury induced tactile allodynia and thermal hyperalgesia may be mediated via different afferent fiber input was tested by evaluating these responses in sham-operated or nerve-injured (L5/L6) rats before or after a single systemic injection of resiniferatoxin (RTX), an ultrapotent analogue of the C-fiber specific neurotoxin, capsaicin. Tactile allodynia, and three measures of thermal nociception, tail-flick, paw-flick and hot-plate responses, were determined before and at various intervals for at least 40 days after RTX injection. Nerve-injured, but not sham-operated, rats showed a long-lasting tactile allodynia and thermal hyperalgesia (paw-flick) within 2-3 days after surgery; responses to other noxious thermal stimuli (i.e., tail-flick and hot-plate tests) did not distinguish the two groups at the stimulus intensities employed. RTX treatment resulted in a significant and long-lasting (i.e. essentially irreversible) decrease in sensitivity to thermal noxious stimuli in both sham-operated and nerve-injured rats; thermal hyperalgesia was abolished and antinociception produced by RTX. In contrast, RTX treatment did not affect the tactile allodynia seen in the same nerve-injured rats. These data support the concept that thermal hyperalgesia seen after nerve ligation, as well as noxious thermal stimuli, are likely to be mediated by capsaicin-sensitive C-fiber afferents. In contrast, nerve-injury related tactile allodynia is insensitive to RTX treatment which clearly desensitizes C-fibers and, therefore such responses are not likely to be mediated through C-fiber afferents. The hypothesis that tactile allodynia may be due to inputs from large (i.e. A beta) afferents offers a mechanistic basis for the observed insensitivity of this endpoint to intrathecal morphine in this nerve-injury model. Further, these data suggest that clinical treatment of neuropathic pains with C-fiber specific agents such as capsaicin are unlikely to offer significant therapeutic benefit against mechanical allodynia.

Spinal opioid mu receptor expression in lumbar spinal cord of rats following nerve injury

Previous studies in rats have shown that spinal morphine loses potency and efficacy to suppress an acute nociceptive stimulus applied to the tail or the paw following injury to peripheral nerves by tight ligation of the L5/L6 spinal nerves. Additionally, intrathecal (i.th.) morphine is ineffective in suppressing tactile allodynia at fully antinociceptive doses in these animals. The molecular basis for this loss of morphine potency and efficacy in nerve injury states is not known. One possible explanation for this phenomenon is a generalized, multi-segmental loss of opioid mu (mu) receptors in the dorsal horn of the spinal cord after nerve injury. This hypothesis was tested here by determining whether nerve injury produces (a) a decrease in mu receptors in the lumbar spinal cord; (b) a decrease in the affinity of ligand-receptor interaction, (c) a decrease in the fraction of high-affinity state of the mu receptors and (d) a reduced ability of morphine to activate G-proteins via mu receptors. Lumbar spinal cord tissues were examined 7 days after the nerve injury, a time when stable allodynia was observed. At this point, no differences were observed in the receptor density or affinity of [3H]DAMGO (mu selective agonist) or [3H]CTAP (mu selective antagonist) in the dorsal quadrant of lumbar spinal cord ipsilateral to nerve injury. Additionally, no change in morphine's potency and efficacy in activating G-proteins was observed. In contrast, staining for mu opioid receptors using mu-selective antibodies revealed a discrete loss of mu opioid receptors localized ipsilateral to the nerve injury and specific for sections taken at the L6 level. At these spinal segments, mu opioid receptors were decreased in laminae I and II. The data indicate that the loss of mu opioid receptors are highly localized and may contribute to the loss of morphine activity involving input at these spinal segments (e.g., foot-flick response). On the other hand, the lack of a generalized loss of opioid mu receptors across spinal segments makes it unlikely that this is the primary cause for the loss of potency and efficacy of mu opioids to suppress multi-segmental reflexes, such as the tail-flick response.

Tactile allodynia, but not thermal hyperalgesia, of the hindlimbs is blocked by spinal transection in rats with nerve injury

Spinal nerve ligation produces signs of neuropathic pain in rats. Different neuronal pathways may underlie the abnormal sensory responses to thermal and tactile stimuli. Here, the possibility that local circuitry in the spinal cord and/or spinal-supraspinal loops might be involved in tactile allodynia and thermal hyperalgesia of the hindpaws was investigated by transecting the spinal cord of sham-operated or L5/L6 nerve ligated rats. Spinal transection completely abolished tactile allodynia in ligated rats. Thermal nocifensive responses were present after transection in ligated and sham-operated rats. Thermal hyperalgesia of the hindpaws was not evident in spinal transected, ligated rats. Tail-withdrawal responses to tactile probing were very robust after spinal transection in both groups, demonstrating loss of descending inhibition. These observations suggest that thermal hyperalgesia of the paw seen after nerve injury involves both spinal and supraspinal circuits, while tactile allodynia depends on a supraspinal loop. This difference may reflect afferent inputs associated with different fiber types.

Differential activities of intrathecal MK-801 or morphine to alter responses to thermal and mechanical stimuli in normal or nerve-injured rats

Nerve ligation injury in rats results in reduced nociceptive and non-nociceptive thresholds, similar to some aspects of clinical conditions of neuropathic pain. Since underlying mechanisms of hyperalgesia and allodynia may differ, the present study investigated the pharmacology of morphine and MK-801 in rats subjected to a tight ligation of the L5 and L6 nerve roots or to a sham-operation procedure. Response to acute nociception was measured by (a) withdrawal of a hindpaw from a radiant heat source, (b) withdrawal of the tail from a radiant heat source or (c) the latency to a rapid flick of the tail following immersion in water at different noxious temperatures. Mechanical thresholds were determined by measuring response threshold to probing the hindpaw with von Frey filaments. Nerve ligation produced a significant, stable and long-lasting decrease in threshold to mechanical stimulation (i.e., tactile allodynia) when compared to sham-operated controls. Standardization of the diameter of the filaments (to that of the largest filament) did not alter the response threshold in nerve-injured animals. Nerve ligation produced decreased response latency of the ipsilateral paw (i.e., hyperalgesia) when compared to that of sham-operated rats. Tail-flick latencies to thermal stimuli induced by water at constant temperatures (48 degrees, 52 degrees or 55 degrees C) or by radiant heat were not significantly different between nerve-injured and sham-operated groups. At doses which were not behaviorally toxic, MK-801 had no effect on tactile allodynia. At these doses, MK-801 blocked decreased paw withdrawal latency to radiant heat in nerve-injured rats, but did not significantly elevate the response threshold of sham-operated rats. Systemic (i.p.) or intracerebroventricular (i.c.v.) doses of morphine previously shown to be antiallodynic in nerve-ligated rats did not affect the response to probing with von Frey filaments in sham-operated controls. Intrathecal (i.t.) morphine did not change paw withdrawal thresholds elicited by von Frey filaments of either nerve-ligated rats (as previously reported) or of sham-operated rats at doses maximally effective against thermal stimuli applied to the tail or foot. Spinal morphine produced dose-dependent antinociception in both nerve-injured and sham-operated groups in the foot-flick test but was less potent in the nerve-injured group. Presuppression of hyperalgesia of the foot with i.t. MK-801 in nerve-injured animals did not alter the potency of i.t. morphine. I.t. morphine was also active in the tail-flick tests with decreased potency in nerve-injured animals and, at some stimulus intensities, with a decreased efficacy as well. These data emphasize the distinction between the inactivity of morphine to suppress mechanical withdrawal thresholds (as elicited by von Frey filaments) and the activity of this compound to block the response to an acute thermal nociceptive stimulus in sham-operated or nerve-injured rats. It appears that nerve ligation injury produces a thermal allodynia/hyperalgesia which is likely dependent upon opioid-sensitive small-diameter primary afferent fibers and a mechanical allodynia which may be largely independent of small-fiber input.

Synergistic antinociceptive interactions of morphine and clonidine in rats with nerve-ligation injury

BACKGROUND

Ligation injury of the L5/L6 nerve roots in rats produces behavioral signs representative of clinical conditions of neuropathic pain, including tactile allodynia and thermal and mechanical hyperalgesia. In this model, intrathecal morphine shows no antiallodynic activity, as well as decreased antinociceptive potency and efficacy. This study was designed to explore the antinociceptive activity of intrathecal clonidine alone or in combination with intrathecal morphine (1:3 fixed ratio) in nerve-injured rats. The aims, with this study, were to use nerve-injured animals to determine: (1) whether the antinociceptive potency and efficacy of intrathecal clonidine was altered, and (2) whether the combination of intrathecal morphine and clonidine would act synergistically to produce antinociception.

METHODS

Unilateral nerve injury was produced by ligation of the L5 and L6 spinal roots of male Sprague-Dawley rats. Sham-operated rats underwent a similar surgical procedure but without nerve ligation. Morphine and clonidine were given intrathecally through implanted catheters alone or in a 1:3 fixed ratio. Nociceptive responses were measured by recording tail withdrawal latency from a 55 degrees C water bath, and data were calculated as % maximal possible effect (%MPE).

RESULTS

Morphine produced a dose-dependent antinociceptive effect in both sham-operated and nerve-injured rats. The doses calculated to produce a 50 %MPE (i.e., A50) (+/-95% confidence intervals [CI]) were 15 +/- 4.9 micrograms and 30 +/- 18 micrograms, respectively. Though morphine was able to produce a maximal response (100%) in sham-operated rats, the maximal response achieved in nerve-injured animals was only 69 +/- 21.9 %MPE. Clonidine produced a dose-dependent effect, with an A50 (+/-95% CI) of 120 +/- 24 micrograms in sham-operated rats. In nerve-ligated rats, clonidine produced a maximal effect that reached a plateau of 55 +/- 10.9 %MPE and 49 +/- 10.2 %MPE at 100 and 200 micrograms, respectively, preventing the calculation of an A50. In sham-operated rats, a morphine-clonidine mixture produced maximal efficacy, with an A50 (+/-95% CI) of 15 +/- 9.2 micrograms (total dose), significantly less than the theoretical additive A50 of 44 +/- 10 micrograms. In L5/L6 nerve-ligated rats, the morphine-clonidine combination produced maximal efficacy, with an A50 (+/-95% CI) of 11 +/- 5.4 micrograms (total dose), which was significantly less than the theoretical additive A50 of 118 +/- 73 micrograms, indicating a synergistic antinociceptive interaction. The intrathecal injection of [D-Ala2, NMePhe4, Gly-ol]enkephalin (DAMGO) produced A50 values of 0.23 microgram (range, 0.09-0.6) and 0.97 microgram (range, 0.34-2.7) in sham-operated and ligated rats, respectively. Phentolamine (4 mg/kg, intraperitoneally) produced no antinociceptive effect alone and attenuated, rather than enhanced, the effect of morphine in both groups of rats.

CONCLUSIONS

These data show that: (1) clonidine, like morphine, loses antinociceptive potency and efficacy after nerve ligation injury, and (2) strongly suggest that a spinal combination of morphine and clonidine synergize under conditions of nerve injury to elicit a significant antinociceptive action when either drug alone may be lacking in efficacy. It is unlikely that the synergy of morphine with clonidine is due to an attenuation of spinal sympathetic outflow by clonidine, because the sympatholytic agent phentolamine produced an opposing effect on morphine antinociception. The data suggest that combinations of morphine and clonidine may prove useful in controlling pain in patients with neuropathic conditions.

[The measurement of natural killer cell activity in peripheral blood and peritoneal fluid of patients with endometriosis]

OBJECTIVE

To investigate the role of natural killer (NK) cell activity in the development of endometriosis.

METHODS

The NK cell activity in peripheral blood (PB) and in peritoneal fluid (PF) of 72 patients with endometriosis was studied by means of MTT-assay and compared with that of infertile women and fertile controls.

RESULTS

The NK cell activity in PB and in PF of patients with endometriosis was lower than that in those of infertile and fertile controls, and decreased as the stage of endometriosis increased. Follow-up of 8 patients with stage II/N endometriosis demonstrated that the NK cell activity in PB had a moderate increase shortly after excision of endometriotic lesions, but decreased again to the preoperative level 6-9 months later.

CONCLUSIONS

Patients with endometriosis have a primary defect in their NK cell function, and the defect may be related to the pathogenesis of the disease.

Antiallodynic effects of a CCKB antagonist in rats with nerve ligation injury: role of endogenous enkephalins

Cholecystokinin (CCK) may act as an endogenous anti-opioid and blockade of CCK receptors can enhance the potency and efficacy of morphine. This effect is blocked by opioid delta (delta) receptor antagonists, suggesting a tonic inhibitory action of CCK to diminish the release and/or availability of endogenous enkephalins. The present studies have further evaluated this possibility by studying the antiallodynic actions of a CCKB antagonist (L365,260) alone, or in the presence of thiorphan (a neutral endopeptidase inhibitor) in a model of peripheral neuropathy. Animals subjected to nerve injury, but not sham controls, exhibited long lasting, stable mechanical allodynia. Intrathecal (i.t.) administration of L365,260 or thiorphan alone did not alter allodynia. However, co-administration of these compounds produced a significant antiallodynic action which was antagonized by receptor selective doses of naltrindole, an opioid delta receptor antagonist. In addition, antisera to [Leu5]enkephalin, but not to [Met5]enkephalin, also blocked the antiallodynic action of thiorphan plus L365,260. These data suggest that blockade of CCKB receptors may enhance the actions or availability of endogenous [Leu5]enkephalin or a like substance which can elicit a significant antiallodynic action via opioid delta receptors when its degradation is by inhibited by thiorphan. The data suggest that delta opioids are involved in regulation of some aspects of nerve-injury induced pain.

Experimental study on the mechanism of cisplatin resistance and its reversion in human ovarian cancer

OBJECTIVE

To explore the mechanism of cisplatin resistance and its reversion in human ovarian cancer.

MATERIALS AND METHODS

A cisplatin resistant cell subline of SKOV3, SKOV3/cp, was established, and a xenograft mice model of human ovarian cancer was established by microencapsulation technology. Various biochemical changes and the effects of modulators on the resistance in the model were observed.

RESULTS

The intracellular platinum accumulation. Pt-DNA adducts and interstrand cross links of DNA (ISC) in SKOV3 was 5.1, 2.4 and 4.8 times respectively of those in SKOV3/cp cell line. Amphotericin B (AmB) and Novobiocin (NVB) could raise platinum accumulation and Pt-DNA adducts concentration in SKOV3/cp and this resulted in reversion of cisplatin resistance.

CONCLUSIONS

The primary factors resulting in SKOV3/cp resistance to cisplatin are the reduction of intracellular drugs and the augmentation of the ability to remove Pt-DNA adducts. AmB and NVB can reverse cisplatin resistance in SKOV3/cp cells.

[Experimental study on the mechanism of cisplatin resistance and its reversion in human ovarian cancer]

OBJECTIVE

To explore the mechanism of cisplatin resistance and its reversion in human ovarian cancer.

METHODS

A xenografted cisplatin resistant mice model of human ovarian cancer, SKOV3/cp, was developed by the microencapsulated technique. The multiple changes of bio-chemical markers in the model were determined, and various modulators for reversion were tested.

RESULTS

Intracellular platinum accumulation in SKOV3 was 5.1 times, Pt-DNA adducts 2.4 times and interstrand cross link of DNA (ISC) 4.8 times of those in cisplatin-resistant cell line, SKOV3/cp. These changes in SKOV3/cp could not be reversed by verapamil. Amphotercin B (AmB) and Novobiocin (NVB) could raise the concentrations of platinum and Pt-DNA adducts in SKOV3/cp, resulting in complete or partial reversion of cisplatin-resistance of SKOV3/cp. There were no differences in total glutathione (GSH) level and in sensitivity to CdCl2 between SKOV3 and SKOV3/cp.

CONCLUSIONS

It is suggested that the primary factor causing SKOV3/cp resistance to cisplatin is the reduction of intracellular platinum accumulation and the augmentation of the ability to remove Pt-DNA adducts. The resistance is not considered to be associated with the multidrug resistant, GSH, metallothionein systems. AmB and NVB can overcome cisplatin resistance of SKOV3/cp in vitro and in vivo.

Regulation of morphine antiallodynic efficacy by cholecystokinin in a model of neuropathic pain in rats

Neuropathic pains have often been classified as opioid-resistant. Here, spinal (intrathecal) actions of morphine and nonmorphine opioids have been studied in a nerve ligation model of neuropathic pain in rats. Mechanical allodynia was evaluated using von Frey filaments. Nerve-injured animals exhibited allodynia that was stable for up to 6 weeks after the surgery. Morphine did not alter allodynia at doses up to 300 nmol (100 micrograms). In contrast, [D-Ala2, NMPhe4, Gly-ol]enkephalin (DAMGO), a high-efficacy mu opioid agonist, produced a significant, dose-related antiallodynic action. [D-Ala2, Glu4]deltorphin (delta agonist) produced a significant antiallodynic effect only at 300 nmol, reaching approximately 70% of the maximum. Coadministration of morphine with a dose of [D-Ala2, Glu4]deltorphin, which was inactive alone, produced a significant and long-lasting antiallodynic action that was antagonized by NTI (delta receptor antagonist); NTI alone had no effect. Although blockade of cholecystokinin-B (CCKB) receptors with L365,260 did not produce effects alone, a significant antiallodynic action was observed when coadministered with morphine; this elevation of nociceptive threshold was abolished by NTI. The finding that DAMGO, but not very large doses of morphine, produced antiallodynic actions suggests that the ability of mu opioids to alleviate the allodynia is related, in part, to efficacy at postsynaptic mu receptors. At an inactive dose, a delta agonist or a CCKB antagonist enhanced morphine antiallodynic efficacy in an NTI-sensitive fashion. CCKB receptor blockade may enhance endogenous enkephalin actions, resulting in enhancement of morphine efficacy through a mu-delta receptor interaction.

Characterization of the antiallodynic efficacy of morphine in a model of neuropathic pain in rats

Neuropathic pains have often been classified as opioid resistant. Here, the ability of systemic (i.p.), intracerebroventricular (i.c.v.) and intrathecal (i.th.) morphine to inhibit mechanical allodynia were studied in a nerve ligation (L5, L6 nerve roots) model of neuropathic pain in rats. Morphine administered i.p. or i.c.v. produced dose-dependent antiallodynia which was readily antagonized by naloxone (5 mg kg-1, i.p. at -10 min). In contrast, i.th. morphine at doses up to 100 micrograms was without effect. These data suggest that the failure of i.th. morphine to produce antiallodynic effects may be due, in part, to the lack of available functional spinal opioid mu-receptors which may occur following nerve injury. In contrast, the antiallodynic actions of i.p. or i.c.v. morphine appear to depend on supraspinal activation of opioid (mu?) receptors and subsequent activation of descending modulatory systems. The inconsistent data seen clinically with morphine in neuropathic pains may be related to the lack of supraspinal/spinal synergy that is normally associated with morphine efficacy in conditions of acute pain.

Inhibition by spinal morphine of the tail-flick response is attenuated in rats with nerve ligation injury

Nerve ligation injury in rats produces increased sensitivity and exaggerated responses to nociceptive stimuli (hyperalgesia) as well as nociceptive responses to normally innocuous stimuli (allodynia) analogous to clinical conditions of neuropathic pain. However, the effect of nerve injury on acute nociception has not been extensively studied. Nerve ligation injury was produced by unilateral ligation of the L5 and L6 spinal roots of the sciatic nerve of male Sprague-Dawley rats. Intrathecal (i.th.) catheters were inserted for spinal drug administration. Response to acute nociception was measured by determining the latency to a rapid flick of the tail (TF) after immersion into a 55 degrees C water bath before (control) and after i.th. morphine administration. No change in baseline response to the nociceptive stimulus was observed in either sham-operated or nerve-injured rats. In sham-operated rats, morphine produced dose-dependent antinociception with a 97 +/- 2.3% maximal possible effect (MPE) at a 60 microgram dose; in these controls A50 (95% CL) was 22 micrograms (17-30 micrograms). Morphine administered to rats with nerve injury also produced dose-dependent increase in TF latency, but an MPE of only 60 +/- 17% was obtained at 100 micrograms; higher doses elicited signs of behavioral toxicity. While it was not possible to produce a proper dose-response curve with i.th. morphine in animals with nerve injury, an estimation of the A50 showed approximately a four-fold loss of potency compared to sham-operated controls. Antinociception was readily reversed by naloxone (5 mg/kg, i.p.) in both groups. These data indicate that nerve ligation injury reduces the potency and efficacy of i.th. morphine. While the reasons for this loss of morphine activity in nerve injured animals are unknown, it is possible to speculate that (a) degeneration of primary afferents subsequent to nerve ligation injury might result in a loss of presynaptic opioid (mu?) receptors in the dorsal horn, thereby reducing the antinociceptive activity of morphine at the spinal level; (b) changes in the efficiency of post-receptor transduction may occur following nerve injury which can reduce opioid efficacy; (c) changes in levels of spinal neurotransmitters (e.g., cholecystokinin) may act to diminish opioid action; or (d) sustained afferent input from the site of the injury may be important in limiting the activity of opioids.

The loss of antinociceptive efficacy of spinal morphine in rats with nerve ligation injury is prevented by reducing spinal afferent drive

Nerve ligation injury in rats may represent a useful model of some clinical neuropathic pains. Activation of N-methyl-D-aspartate (NMDA) receptors may maintain central sensitivity and contribute to neuropathic pain. Here, nerve injury was produced by unilateral ligation of the L5 and L6 spinal roots of the sciatic nerve of rats. Catheters were inserted for intrathecal (i.th.) or local delivery of drugs at the site of nerve ligation. Acute nociception was measured by the 55 degrees C water tail flick test in sham-operated and nerve-injured rats, and allodynia was determined by measuring response to von Frey filaments. In sham-operated rats, morphine (30 micrograms, i.th.) produced a 60 +/- 14.4% MPE (maximal possible effect). MK-801 pretreatment did not alter tail-flick latency or morphine antinociception in sham-operated rats. In nerve-injured rats, morphine (30 micrograms, i.th.) produced a significantly lower antinociceptive effect than in controls (34 +/- 6.3% MPE). While MK-801 alone did not alter tail-flick latency in nerve-injured rats, it significantly enhanced the antinociceptive effect of morphine to 84 +/- 16.0% MPE. Bupivacaine (0.2 ml, 0.75% w/v) at the site of injury also significantly increased the efficacy of morphine (100 +/- 0% MPE) without affecting tail flick latency alone. Bupivacaine administered at the site of injury also produced a significant antiallodynic effect of 94 +/- 7.4% MPE. The reduction in antinociceptive efficacy of i.th. morphine in nerve injured rats may be due, in part, to an ongoing spontaneous activity initiated by ectopic foci at the site of injury, and possible NMDA receptor-mediated activity of spinal neurons.

[Suppressive effects of adenosine on nonspecific and humoral immunities in mice]

Adenosine (Ade) 1.3, 13, 130 mg.kg-1 ip inhibited the ability of peripheral leukocytes and peritoneal macrophages in phagocytosing the Staphylococcus albus with [3H]TdR incorporation in mice, declined the hemolytic ability of plaque-forming cells and the production of antibody in mice immunized by sheep erythrocytes. Ade 13, 130 mg.kg-1 ip decreased the mouse serum muramidase (lysozyme) concentration. Dipyridamole (Dip) 10 mg.kg-1 ip attenuated the effects of Ade 130 mg.kg-1 on humoral immunity reaction, but the nonspecific immunity was not attenuated. These results showed that the uptake of Ade may play an important role in the effects of Ade on humoral immunity reaction. Aminophylline (Ami) 100 mg.kg-1 ip attenuated the effects of Ade 130 mg.kg-1 on hemolytic ability of plaque-forming cells and the ability of peripheral leukocytes in phagocytosing Staphylococcus albus. These results suggested that the effects of Ade on murine humoral and nonspecific immunity reaction were mediated by Ade A2 receptor (A2DR).

[Suppressive effects of safflower yellow on immune functions]

Safflower yellow (SY) extracted from Carthamus tinctorius L contained chalconoid compounds, 75% of which was safflomin A. SY ip 50-450 mg.kg-1.d-1 x 6-8 d in mice decreased serum lysozyme concentration and phagocytosing functions of both peritoneal macrophages and peripheral leukocytes; diminished the production of plaque forming cells, specific rosette forming cells, and antibody; inhibited delayed type hypersensitivity reaction and the activation of T suppressor cells elicited by supraoptimal immunization. Experiments in vitro showed inhibitory effects on [3H]TdR incorporation during human peripheral T- and B-lymphocyte proliferation by SY 0.03-3.0, 0.1-2.0 mg.ml-1 respectively, murine mixed lymphocyte culture response and the production of interleukin-2 by SY 0.1-2.5 mg.ml-1. In conclusion, SY produced declines in both nonspecific and specific immune functions.

[Influence of aminophylline on immune function of mice]

The effects of aminophylline (Ami) on immune systems in normal NIH mice were studied. Ami ig 25, 50 and 100 mg/(kg.d) x 8-10 d increased hemolytic ability of plaque forming cells and antibody concentration while it decreased the delayed type hypersensitivity (DTH) reaction and peripheral white blood cells phagocytosing function. Ami 1, 5, 10 micrograms/ml also promoted lymphocyte transformation of [methyl-3H] TdR incorporation induced by PHA in vitro.